Wading Into the Gene Pool: Progress and Constraints Using Wild Species

Crop Science ◽  
2017 ◽  
Vol 57 (3) ◽  
pp. 1039-1041 ◽  
Author(s):  
Stephanie L. Greene ◽  
Marilyn L. Warburton
Keyword(s):  
2011 ◽  
Vol 11 (1) ◽  
pp. 15-25 ◽  
Author(s):  
R. van Treuren ◽  
A. J. M. van der Arend ◽  
J. W. Schut

Genebanks serve as a rich source of diversity that can be exploited for crop improvement. However, large numbers of accessions usually have to be evaluated to find material with the characters of interest, and therefore, enhanced trait information can facilitate the more efficient selection of accessions by users. In this study, we report on the distribution of resistances to 28 races of downy mildew among 1223 genebank accessions of cultivated lettuce (Lactuca sativaL.) and 14 related wild species. Due to modern plant breeding, the overall level of resistance of cultivars released after 1950 appears to have increased two- to three-fold compared with varieties from earlier periods. Although fully resistant reactions could be observed among the accessions of cultivated lettuce for each of the 28 investigated races, the resistance probability was more than two-fold higher on average for accessions from the wild gene pool. In general, species of the primary gene pool appeared less resistant than those of the secondary or tertiary gene pool. Probabilities for examinedLactucaspecies ranged from 0.29 forL. serriolato 1.00 forL. perenniscompared with 0.19 for cultivated lettuce, with lower overall resistance probabilities observed only forL. altaica,L. dregeanaandL. tenerrima. ForL. serriola, the closest relative of cultivated lettuce and the wild species with the highest number of examined accessions, resistance probabilities to each of the investigated downy mildew races were relatively high for populations originating from Eastern Europe and Northern Asia.


1990 ◽  
Vol 17 (1) ◽  
pp. 35-38 ◽  
Author(s):  
C. Corley Holbrook ◽  
James P. Noe

Abstract Peanut root-knot nematode (Meloidogyne arenaria (Neal) Chitwood race 1) is a serious pathogen in commercial peanut (Arachis hypogaea L.) production. There is no peanut cultivar with resistance to this nematode. The primary constraint in the development of resistant cultivars has been the absence of identified sources of resistance in A. hypogaea and related wild species. The objective of this study was to examine the wild Arachis spp. collection of the Coastal Plain Experiment Station for sources of resistance to M. arenaria. Thirty-six wild Arachis spp. genotypes were compared with the susceptible cv. Florunner for resistance to M. arenaria reproduction and galling response in two greenhouse tests. A. monticola Krap. et Rig., a member of the second-order gene pool, was the only wild species tested which did not have a gall index and egg-mass index significantly lower than that of A. hypogaea. There was no significant difference between A. monticola and A. hypogaea for the number of eggs per root system or per gram of fresh root weight. In addition, the host efficiency of A. monticola was 3.49, indicating a high level of susceptibility. All genotypes examined from the third-order gene pool species (A. cardenasii Krap. et Greg. nom. nud., A. duranensis Krap. et Greg. nom. nud., A. helodes Martius ex Krap. et Rig. and A. villosa Benth.) exhibited significantly less plant damage and nematode reproduction than A. hypogaea. Except for one A. villosa genotype, all entries from the third-order gene pool exhibited high levels of resistance to M. arenaria based on a host efficiency less than 1.00. All fourth-order gene pool accessions examined (A. burkartii Handro, A. glabrata Benth., and A. hagenbeckii Harms.) exhibited high levels of resistance to M. arenaria. These results indicate that resistance to M. arenaria is prevalent in both the third- and fourth-order gene pools of peanut. These results increase the probability of success in developing peanut cultivars with resistance to M. arenaria since species in the third-order gene pool are cross compatible with A. hypogaea. Based on genetic theory, these results also increase the probability of resistance to M. arenaria in the first-order gene pool. Therefore, further screening for resistance to M. arenaria in A. hypogaea is recommended.


2021 ◽  
Vol 11 (4) ◽  
Author(s):  
Ye Chu ◽  
David Bertioli ◽  
Chandler M Levinson ◽  
H Thomas Stalker ◽  
C Corley Holbrook ◽  
...  

Abstract Genome instability in newly synthesized allotetraploids of peanut has breeding implications that have not been fully appreciated. Synthesis of wild species-derived neo-tetraploids offers the opportunity to broaden the gene pool of peanut; however, the dynamics among the newly merged genomes creates predictable and unpredictable variation. Selfed progenies from the neo-tetraploid Arachis ipaënsis × Arachis correntina (A. ipaënsis × A. correntina)4x and F1 hybrids and F2 progenies from crosses between A. hypogaea × [A. ipaënsis × A. correntina]4x were genotyped by the Axiom Arachis 48 K SNP array. Homoeologous recombination between the A. ipaënsis and A. correntina derived subgenomes was observed in the S0 generation. Among the S1 progenies, these recombined segments segregated and new events of homoeologous recombination emerged. The genomic regions undergoing homoeologous recombination segregated mostly disomically in the F2 progenies from A. hypogaea × [A. ipaënsis × A. correntina]4x crosses. New homoeologous recombination events also occurred in the F2 population, mostly found on chromosomes 03, 04, 05, and 06. From the breeding perspective, these phenomena offer both possibilities and perils; recombination between genomes increases genetic diversity, but genome instability could lead to instability of traits or even loss of viability within lineages.


2021 ◽  
Author(s):  
Aanchal Chauhan ◽  
Deepa Sharma ◽  
Sanjeev Kumar Banyal ◽  
Madhvi . ◽  
Divya .

Wide hybridization is an important plant breeding method as it helps in broadening the gene pool of a crop when the desired variation is not sufficient or absent within the same gene pool. Wild genetic resources are the potential source of desirable genes for various characters of crop plants. It plays a significant role in transferring traits of interest like disease and insect resistance, improved quality, earliness, dwarfness, increased yield, abiotic stress tolerance and manipulation in mode of reproduction etc. in crop plants. It has been instrumental in transferring disease resistance from wild species into many vegetable crops. For example, resistance to late blight, leaf roll and potato virus X, yellow vein mosaic virus and powdery mildew in okra, bacterial wilt, tomato leaf curl virus, early and late blight in tomato has been transferred from wild species into cultivated species. Wild species has been used to improve the quality traits of some crops like carotenoid content in carrot and tomato, starch content in potato etc. Sometimes distant hybridization leads to creation of entirely new crop species. Chromosome elimination technique followed by wide hybridization has been successfully used in the production of double haploids in some crops. However there are some lacunae in wide hybridization such as cross incompatibility, hybrid inviability, hybrid sterility and hybrid breakdown. Some special techniques viz. ploidy manipulation, pistil manipulation, growth regulators treatments, bridge crossing, grafting and embryo rescue have to be adopted to make distant hybridization successful in such cases.


2020 ◽  
Vol 90 (1) ◽  
Author(s):  
Natale Emilio Baldaccini

Wild rock doves still breed in suitable habitats along southern and insular Italy, even if their colonies are threatened by the genetic intrusion of feral pigeons. One of their prominent behaviours is the daily foraging flights from colonial to feeding grounds which involves coming into contact with man-made buildings. These are exploited firstly as roosting places near crop resources and later for nesting. This incipient synanthropy is not extended to direct food dependence on humans, by which they tend to remain independent. In the same way that ferals genetically intruded the wild colonies, in urban habitats, rock doves mix with ferals because of the large interbreeding possibilities. In the natural range of the wild species, this has occurred since the appearance of the feral form of pigeons and still continues with the residual populations of rock doves, representing their endless contribution to the feral populations, at least until the dissolution of the gene pool of the primordial form of wild rock dove.


1992 ◽  
Vol 70 (2) ◽  
pp. 240-244 ◽  
Author(s):  
J. M. Leggett ◽  
G. Ladizinsky ◽  
P. Hagberg ◽  
M. Obanni

Wild taxa of crop plants have been valuable sources of genes for cultivar improvement in several species. Genes for yield, resistance to pests and diseases, protein quality and quantity, maturity and other characteristics have been transferred from wild species of Avena to the cultivated oat crop (A. sativa L.). In an attempt to preserve some of the genetic variability in the wild species and taxa of Avena, two collecting missions were organised in 1985 and 1988. During the 1985 expedition 49 accessions were collected on mainland Spain and the Canary Islands, and 74 accessions were collected in Morocco. In 1988, a further 64 accessions were collected in Morocco. These accessions included representatives from 10 of the 14 known biological species of Avena and 16 of the 30 generally accepted taxonomic entities. These collections have increased the size of the available gene pool and extended the known geographical distribution of some of the species. Key words: Avena, distribution, germ plasm, genetic resources.


1970 ◽  
Vol 6 ◽  
pp. 24-27 ◽  
Author(s):  
Bal K Joshi

Knowledge on crop gene pool helps to develop varieties, to know the potential sources forbreeding materials and to develop strategy for sustainable use and conservation. The amount ofgenetic diversity presents depends on the number and diversity of the original ancestorsinvolved in the creation of a germplasm pool, existing landraces and wild species. The objectiveof this research was to study the diversity of rice gene pool present in the Nepalese improvedrice cultivars and landraces adapted to Tarai and Inner Tarai (<1000 m). Pedigrees of 28Nepalese rice cultivars were examined and surveyed the literature for distribution of landracesand wild relatives of rice. Crosses among indica rice gene pool are more common and use ofjaponica and nivara species were less common. There are 28 improved rice cultivars, >500landraces, and 6 wild species and relatives of rice adapted to Tarai and Inner Tarai. Eightcountries are the origins for 28 cultivars. In Nepal 4 cultivars were bred and developed using alocal landrace and exotic genotypes. A total of 35 ancestors originated in 11 different countrieswere used to develop these 28 cultivars. Highest number of ancestors was from India. Use ofancestors of both sativa and nivara species having indica and japonica types indicated thecollection of wide gene pool. Most of the ancestors were sativa (60.00%) and indica (65.71%).Genetic erosion is observed in rice diversity therefore, in situ, on farm and ex situ conservationsare necessary for maintaining the genetic variation. Utilization of local landraces in breedingprogram may be the good way of genetic resources conservation. Gene pool from theselandraces along with international gene pool could make towards success in developing highyielding cultivars with wide adaptability and/or site specific. In this study, cultivars andlandraces surveyed represent a wide range of variation for different areas of origin andadaptation. This genetic diversity is very useful for further rice improvement and should beconserved both ex situ and in situ.Key words: Ancestor; Landrace; Nepalese rice cultivar; Rice gene pool; Tarai and Inner TaraiDOI: 10.3126/narj.v6i0.3339Nepal Agriculture Research Journal Vol.6 2005 pp.10-22


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